How are product pages set up in Commerce?
Commerce separates customer-facing Catalog (or product pages) and the internal Products that it requires to calculate totals and handle orders by design.
The Catalog is your front-end. It's how customers browse through what your webshop has to offer, including product information, different variations, photos or videos, reviews, and so on. How you build this catalog is completely up to you: it can consist of resources, Collections, MIGX TVs, SimpleCart product resources, a POS or ERP system, custom tables or third party database... the possibilities are limited to your imagination (and skills and/or budget).
Products are rather simple objects consisting of a product's name, description, SKU, stock level, and price. These products are what Commerce cares about. When a customer sees an item they'd like to purchase in your catalog, they will add this Product to their cart.
Commerce offers a few options for linking together your catalog and the product as well as the flexibility to build something completely custom. For simple shops, we recommend using the Product List TV to add products to your resources. The Matrix TV is a bit more complex to set up, but also a lot more powerful with built-in variations. Finally for very simple shops/products, a resource product will make Commerce fill a product record with information from a resource (including TVs).